NL_LANGINFO(3) Linux Programmer's Manual NL_LANGINFO(3)
NAME
nl_langinfo, nl_langinfo_l - query language and locale information
SYNOPSIS
#include <langinfo.h>
char *nl_langinfo(nl_item item);
char *nl_langinfo_l(nl_item item, locale_t locale);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
nl_langinfo_l():
Since glibc 2.24:
_POSIX_C_SOURCE >= 200809L
Glibc 2.23 and earlier:
_POSIX_C_SOURCE >= 200112L
DESCRIPTION
The nl_langinfo() and nl_langinfo_l() functions provide access to lo-
cale information in a more flexible way than localeconv(3). nl_lang-
info() returns a string which is the value corresponding to item in the
program's current global locale. nl_langinfo_l() returns a string
which is the value corresponding to item for the locale identified by
the locale object locale, which was previously created by newlocale(1).
Individual and additional elements of the locale categories can be
queried. setlocale(3) needs to be executed with proper arguments be-
fore.
Examples for the locale elements that can be specified in item using
the constants defined in <langinfo.h> are:
CODESET (LC_CTYPE)
Return a string with the name of the character encoding used in
the selected locale, such as "UTF-8", "ISO-8859-1", or
"ANSI_X3.4-1968" (better known as US-ASCII). This is the same
string that you get with "locale charmap". For a list of char-
acter encoding names, try "locale -m" (see locale(1)).
D_T_FMT (LC_TIME)
Return a string that can be used as a format string for strf-
time(3) to represent time and date in a locale-specific way (%c
conversion specification).
D_FMT (LC_TIME)
Return a string that can be used as a format string for strf-
time(3) to represent a date in a locale-specific way (%x conver-
sion specification).
T_FMT (LC_TIME)
Return a string that can be used as a format string for strf-
time(3) to represent a time in a locale-specific way (%X conver-
sion specification).
AM_STR (LC_TIME)
Return a string that represents affix for ante meridiem (before
noon, "AM") time. (Used in %p strftime(3) conversion specifica-
tion.)
PM_STR (LC_TIME)
Return a string that represents affix for post meridiem (before
midnight, "PM") time. (Used in %p strftime(3) conversion speci-
fication.)
T_FMT_AMPM (LC_TIME)
Return a string that can be used as a format string for strf-
time(3) to represent a time in a.m. or p.m. notation a locale-
specific way (%r conversion specification).
ERA (LC_TIME)
Return era description, which contains information about how
years are counted and displayed for each era in a locale. Each
era description segment shall have the format:
direction:offset:start_date:end_date:era_name:era_format
according to the definitions below:
direction Either a "+" or a "-" character. The "+" means that
years increase from the start_date towards the
end_date, "-" means the opposite.
offset The epoch year of the start_date.
start_date A date in the form yyyy/mm/dd, where yyyy, mm, and
dd are the year, month, and day numbers respectively
of the start of the era.
end_date The ending date of the era, in the same format as
the start_date, or one of the two special values
"-*" (minus infinity) or "+*" (plus infinity).
era_name The name of the era, corresponding to the %EC strf-
time(3) conversion specification.
era_format The format of the year in the era, corresponding to
the %EY strftime(3) conversion specification.
Era description segments are separated by semicolons. Most lo-
cales do not define this value. Examples of locales that do de-
fine this value are the Japanese and Thai locales.
ERA_D_T_FMT (LC_TIME)
Return a string that can be used as a format string for strf-
time(3) for alternative representation of time and date in a lo-
cale-specific way (%Ec conversion specification).
ERA_D_FMT (LC_TIME)
Return a string that can be used as a format string for strf-
time(3) for alternative representation of a date in a locale-
specific way (%Ex conversion specification).
ERA_T_FMT (LC_TIME)
Return a string that can be used as a format string for strf-
time(3) for alternative representation of a time in a locale-
specific way (%EX conversion specification).
DAY_{1-7} (LC_TIME)
Return name of the n-th day of the week. [Warning: this follows
the US convention DAY_1 = Sunday, not the international conven-
tion (ISO 8601) that Monday is the first day of the week.]
(Used in %A strftime(3) conversion specification.)
ABDAY_{1-7} (LC_TIME)
Return abbreviated name of the n-th day of the week. (Used in
%a strftime(3) conversion specification.)
MON_{1-12} (LC_TIME)
Return name of the n-th month. (Used in %B strftime(3) conver-
sion specification.)
ABMON_{1-12} (LC_TIME)
Return abbreviated name of the n-th month. (Used in %b strf-
time(3) conversion specification.)
RADIXCHAR (LC_NUMERIC)
Return radix character (decimal dot, decimal comma, etc.).
THOUSEP (LC_NUMERIC)
Return separator character for thousands (groups of three dig-
its).
YESEXPR (LC_MESSAGES)
Return a regular expression that can be used with the regex(3)
function to recognize a positive response to a yes/no question.
NOEXPR (LC_MESSAGES)
Return a regular expression that can be used with the regex(3)
function to recognize a negative response to a yes/no question.
CRNCYSTR (LC_MONETARY)
Return the currency symbol, preceded by "-" if the symbol should
appear before the value, "+" if the symbol should appear after
the value, or "." if the symbol should replace the radix charac-
ter.
The above list covers just some examples of items that can be re-
quested. For a more detailed list, consult The GNU C Library Reference
Manual.
RETURN VALUE
On success, these functions return a pointer to a string which is the
value corresponding to item in the specified locale.
If no locale has been selected by setlocale(3) for the appropriate cat-
egory, nl_langinfo() return a pointer to the corresponding string in
the "C" locale. The same is true of nl_langinfo_l() if locale speci-
fies a locale where langinfo data is not defined.
If item is not valid, a pointer to an empty string is returned.
The pointer returned by these functions may point to static data that
may be overwritten, or the pointer itself may be invalidated, by a sub-
sequent call to nl_langinfo(), nl_langinfo_l(), or setlocale(3). The
same statements apply to nl_langinfo_l() if the locale object referred
to by locale is freed or modified by freelocale(3) or newlocale(3).
POSIX specifies that the application may not modify the string returned
by these functions.
ATTRIBUTES
For an explanation of the terms used in this section, see at-
tributes(7).
+--------------+---------------+----------------+
|Interface | Attribute | Value |
+--------------+---------------+----------------+
|nl_langinfo() | Thread safety | MT-Safe locale |
+--------------+---------------+----------------+
CONFORMING TO
POSIX.1-2001, POSIX.1-2008, SUSv2.
NOTES
The behavior of nl_langinfo_l() is undefined if locale is the special
locale object LC_GLOBAL_LOCALE or is not a valid locale object handle.
EXAMPLES
The following program sets the character type and the numeric locale
according to the environment and queries the terminal character set and
the radix character.
#include <langinfo.h>
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
int
main(int argc, char *argv[])
{
setlocale(LC_CTYPE, "");
setlocale(LC_NUMERIC, "");
printf("%s\n", nl_langinfo(CODESET));
printf("%s\n", nl_langinfo(RADIXCHAR));
exit(EXIT_SUCCESS);
}
SEE ALSO
locale(1), localeconv(3), setlocale(3), charsets(7), locale(7)
The GNU C Library Reference Manual
COLOPHON
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GNU 2020-04-11 NL_LANGINFO(3)